The invention relates to a mechanical pipette.
Pipettes are handheld or stationary dosing devices that in particular are used in the laboratory for dosing liquids. “Liquids” mean liquid media in the form of samples that are single-phase liquids or liquid mixtures, or multiphase liquid mixtures (such as emulsions) or liquid-solid mixtures (such as suspensions) or liquid-gas mixtures (such as foams).
Air displacement pipettes have a seat for releasably holding a pipette tip. A displacement unit for air is integrated in the pipette and, communicating by means of a channel, is connected to a hole in the seat. The air cushion is displaced by means of the displacement unit so that liquid is aspirated into, or discharged from, a tip opening in the pipette tip depending on the direction of displacement of the air cushion. The displacement unit is usually a cylinder having a plunger displaceable therein. The plunger is driven by means of a drive unit. The designation “air displacement pipette” is based on the air cushion between the liquid and the displacement unit.
Positive displacement pipettes work together with syringes that have a syringe cylinder and a syringe plunger that is displaceable therein. The syringes can be coupled to or respectively released from the positive displacement pipettes. The syringe cylinder is held in the positive displacement pipette and the syringe plunger is held in a plunger seat that can be displaced by means of a drive unit. By means of the drive unit, the syringe plunger is moved back and forth so that the liquid is aspirated into, or respectively discharged from, a hole in the tip. The designation “direct displacement pipette” is based on that there is no air cushion between the liquid and syringe piston, and the syringe piston directly displaces the liquid.
When designed as a dispenser, the positive displacement pipette has a drive unit that enables a stepwise discharge in partial amounts of a complete quantity of liquid aspirated by the tip.
Pipettes are known with a manually driven mechanical drive unit, or an electromechanically driven drive unit, or a manually driven mechanical drive unit with electromechanical support (servodrive). In addition, there are pipettes with a fixed and adjustable volume. In addition, dispensers are known in which the partial amount to be dispensed is adjustable. Furthermore, there are single-channel pipettes for use with only a single pipette tip, and multichannel pipettes for simultaneous use with several pipette tips or syringes.
Pipette tips or syringes preferably consist of plastic and can be thrown away as a disposable item after use, or respectively can be replaced with a fresh pipette tip or syringe. Pipette tips or syringes are provided in various sizes for dosing within various volume ranges.
Pipettes have operating elements for controlling the aspiration and discharge of liquid, and possibly for releasing the pipette tip or syringe from the pipette. They also have operating elements that can be used for the manual entry of user parameters (such as the dosing volume, dosing speed, material constants of the liquid, calibration data), and/or modes of operation (such as pipetting, dispensing, titrating, mixing), and/or operating procedures for processing samples (such as aspirating, mixing and discharging liquids). Furthermore, they are provided with a display unit that serves to display operating data (such as user parameters, mode of operation, operating procedures, operating state) of the pipette.
The operating and display units are primarily arranged on the top end of the pipette. The pipette housing generally widens there to accommodate these elements. Pipettes are known with an approximately rod-shaped housing that has a housing head on the top which is angled like a lectern and may protrude at one side. Electrical switches or respectively keys and at least one display are accommodated in this housing head. Liquid crystal displays (LCDs) are conventional displays. Such pipettes are described in EP 1 825 915 A2, EP 1 859 869 A1 and EP 1 878 500 A1. As pipettes become increasingly complex, operating and display units are generally used with more complex entry devices and larger display units.
A disadvantage is that the pipettes protrude at the top due to the operating and display units that are contained therein, are heavy, and are nevertheless difficult to operate and read since they are small. This makes the pipettes difficult to handle, and there is a potential risk of misuse. In addition, a substantial part of the cost of the pipettes arises from the operating and display units. Complex tasks such as creating routines and programs with the integrated operating and display units are difficult to master. If pipettes are equipped with a smaller operating and display unit, this further reduces the ease of operation.
DE 199 11 397 A1 describes an autonomous pipette with a device control and a sensor unit for capturing operating data that has a wireless interface for transmitting data and/or for controlling the device. The pipette can be easier to control using this interface by means of remote control. The autonomous pipette can be used in a conventional manner without remote control. The autonomous pipette requires operating and display units to do this.
EP 0 999 432 B1 describes an electronic dosing system where routines for performing operating procedures can be entered into a manual dosing device by means of a data processing system via contacting or wireless data interfaces. In addition, operating parameters can be entered into the manual dosing device and the manual dosing device can be controlled by means of the data processing system. The operating parameters are user parameters (such as dosing volumes, dosing speeds), device-type specific parameters (such as parameters determining the plunger movement, parameters determining the quantity, parameters relating to the monitoring of operating states), or device-specific parameters (such as device identification, an ID code for a saved set of parameters). The manual dosing device has its own operating and display units.
A similar dosing system is described in WO 2005/052781 A2. The pipette is also provided with its own operating and display units.
U.S. Pat. No. 7,640,787 B2 describes a verification unit for a pipette. The pipette has means for measuring a volume displaced by the plunger of the pipette, for comparing the measurement with a desired value, and for displaying an error. The reference to an error is displayed by an LCD display on the pipette. In addition, the result of the comparison can be transmitted wirelessly via an interface to a computer for recording. The pipette has its own operating units and its own meter for displaying the liquid volume to be released.
U.S. Pat. No. 4,821,586 describes a pipette system in which a pipette is controlled by a programmed control unit to execute a dosing function selected from a set. This can be for example pipetting individual liquid volumes, dispensing several partial volumes of an aspirated liquid volume, and dilutions and titrations. The control unit also allows new programs for dispensing functions to be written and saved. The control unit contains the controls for the pipette, and is connected via a flexible electrical cable to the motor, switches and lamps of the pipette.
WO 89/10193 describes a pipetting apparatus comprising a stationary unit having a plunger pump, a stepping motor for driving the plunger pump, and a microprocessor for controlling the stepping motor. By means of an entry box that is connected via an electric cable to the microprocessor, data and programs can be entered into the microprocessor. The entry box comprises a display that requests control commands, reproduces the response, and displays the status of the device. A pipette handle has electronic operating elements to trigger various functions including aspiration, discharge and mixing functions. The electronic operating elements are connected to the microprocessor by means of a second electric cable, and the pipette handle is connected to the plunger pump by means of a pneumatic hose. A pipette tip is connectable to a connector of the pipette handle. The stationary unit with the plunger pump and microprocessor, the entry box and the handle are therefore device components that are separate from each other and are connected to each other by means of flexible leads.
DE 195 06 129 A1 describes a toothbrush that has a pressure sensor in its hand part to determine the correct pressure when brushing. The determined pressure values are supplied by means of a transmitter and a transmission antenna on the hand part to an external display unit provided with a reception antenna. This indicates whether brushing is occurring with sufficient pressure. In addition, the time of brushing can be detected and signaled for different tooth regions.
WO 2008/131874 A1 describes a method for the wireless, unidirectional transmission of data between a transmitter and a receiver, wherein the transmitter sequentially transmits a data record to be transmitted several times over a plurality of transmission channels, and the receiver receives data records on only one transmission channel. The number of transmission channels used is less than the number of repetitions with which the transmitter transmits the data record, and a sequence of transmission channels is used within which the sequence of transmission channels used is specified. Furthermore, it describes a toothbrush having a transmitter for executing the aforementioned procedure and a system consisting of a toothbrush and a separate auxiliary device, wherein a transmitter is in the toothbrush and a receiver is in the auxiliary device. The auxiliary device is provided with a display unit for displaying the transmitted data. For example, the pressure is determined in the toothbrush with which a user presses the brush attachment against the teeth while brushing, and/or the brushing time, and/or the charge of an accumulator contained in the handle for supplying the electrical toothbrush with power.
WO 98/257 36 A1 describes an electrical shaving system having an electric shaver and a remote control having a display unit for displaying specific data. The display unit displays status messages about the razor, and provides the user with feedback while shaving. The remote control can also be provided with buttons, keys or slider controls for setting the shaving parameters of the razor. Sensors for ambient conditions can also be contained in the remote control to supply the electric razor with information that is relevant for shaving comfort. The exchange of data between the remote control and razor can be wireless, and possibly bidirectional.